Method and apparatus for the production of filaments and nonwoven fabrics



Aug. 24, 1954 F. w. MANNING METHOD AND APPARATUS FOR THE PRODUCTION OFFILAMENTS AND NONWOVEN FABRICS 2 Sheets-Sheet 1 Filed Sept. 16, 1950 1 2.4 Q 74 w H N E, .9. p 8% m N w F. W. MANNING METHOD AND APPARATUS FORTHE PRODUCTION OF FILAMENTS AND NONWOVEN FABRICS 2 Sheets-Sheet 2INVENTOR I Aug. 24, 1954 Filed Sept. 16, 1950 r P: Q a a Id. H

Patented Aug. 24, 1954 METHOD AND APPARATUS FOR THE PRO- DUCTION IOFFILAME FABRICS NTS AND NONW'OVEN FredW. Manning, Palo Alto, Calif.Application September 16, 1950, Serial N0. 185,240 34 Claims. (Cl.154-101) My invention relates particularly to improved methods andapparatus for producing stretchoriented filaments and fabrics madetherefrom. This application is a continuation-impart of my copendingapplications: Serial Nos. 663,302 and 702,205, filed April 19, 1946, andOctober 9, 1946, respectively; and subsequently issued as patents, Nos.2,522,526 and 2,522,527, respectively; and ap plication Serial No.742,247, filed April 18, 1947, now abandoned in favor of the presentapplication. Other modifications of the present invention are disclosedin my U. S. applications, Serial Nos. 384,882; 414,717; 425,374, filedOctober 8, 1953; March 8, 1954; and April 26, 1954, respectively.

Stretch-orientation of a filament ordinarily commences at the moment afilament can be sufficiently tensioned to assume a substantiallystraight line between horizontal holding and pulling means without theaid of support between the two said means. This may be at the moment itleaves the spinneret, and for sometime thereafter the filament maycontinue to be in a plastic and an adhesive condition, as indicated bythe distance usually maintained between the spinneret and first wind-upbobbin to prevent sticking of the adjacent filaments; and so long as afilament is maintained in this plastic and adhesive condition, or isattached to a source of supply in this plastic and adhesive condition,the filament or source of supply may be drawn out indefinitely. However,once the filament has become set, additional stretching will usuallybring it to its initial point of elasticity, and from there until itselastic limit has been reached it may be truly elastic, returning to itsinitial point of elasticity when the tension has been removed.

Smooth surface solid filaments cannot ordinarily be stretch-oriented andpropelled simulta neously by force of a fiuid stream. Therefore, priorpractice has been either to deposit a web of unoriented filaments on abacking which had strength, or to build up a coating of comparativelygreat strength on the web. The latter method resulted in an imperviousweb which was often undesirable, and either way was costly, especiallywhen the spinning and spraying solutions contained large amounts ofexpensive, explosive, and non-recoverable solvents. The result was thatthe strength of a finished covering produced by filaments propelled anddeposited by means of a fiuid stream always existed in the backing, orthe coating, rather than in the fabric.

As distinguished from such prior practice, it is an object of myinvention to provide a methiii . poses; adsorptive solids, such ascarbon, silica od whereby a fibre-forming material is attached topulling solids, the material disrupted or attenuated into filamentswhich adhere to the solids, and the solids propelled by an elastic orliquid fluid stream so as to exert a greater stretching force on thefilaments than can be exerted by the fluid without their aid. Thepropulsion fluid may then be used to deposit the stretch-orientedfilaments either in a plastic and adhesive condition, ori'n a set andadhesive condition, or the filaments may be made adhesive afterdeposition to cause them to adhere at their intersections to form anintegral fabric.

The proposed fabric will require neither backing nor coating for itsstrength, and may be made impervious or otherwise treated by a coatingof the usual thermoplastics or thermosetting materials, such as acopolymer of vinyl chloride and vinyl acetate, or a phenol formaldehyderesin; or it may be coated and impregnated by: water repellents, such asa silicone vapor; fire retardants, such as ammonium sulfamate; wettingagents, such. as dioctyl sodium sulfosuccinate; etc. Other objects of myinvention will become apparent from the following description.

In accordance with my invention, the fibreforming material used for theproduction of the filaments and integral fabrics may be organic orinorganic, and thermoplastic or thermosetting, such as the usualplastics extruded into filaments, films, and foils. Some of the mostcommon of these are: polymeric amides, vinylidene chloride,polyethylene, glass, quartz, etc, spun from a molten state;cellulose-acetate, vinyl-chlorideacetate resins, etc., spun from anacetone solution; protein-base materials, petroleum derivatives, etc.All such materials can also be sprayed in droplets or otherwise used forcoating and impregnation purposes, and there are many materials, such asenamels, paints, etc, which can be used for such purposes but cannot bespun into filaments.

Some of the pulling solids which can be used for stretch-orientingfilaments and may be in corporated and bonded thereafter by them intointegral fabrics are: protein fibres, such as shredded scrap leather,used in the'manufacture of leather goods; mineral solids, such as asbestos, vermiculite, perlite, etc, for fireproof insulating coverings;vegetable fibres, such as cotton, wood, yucca, sisal, etc, for packagingpurgel, etc., for adsorbing odors, moisture, etc. also for packagingpurposes; purifying agents, such :as carbon, diatomaceous earth, fullersearth, etc,

for filter fabrics; abrasives, such as silica, carbide, corundum, etc.,for sanding belts and safety walks; stretch-oriented filaments having ahigher softening point than the filaments to be stretchoriented andrequired to give strength, warmth or beauty to the finished fabric;fertilizer pellets, which may or may not have seeds encased therein, forfabrics to be sprayed over freshly seeded ground, or ground to be seededand protected thereby.

Other types of pulling solids that may be separated from the filamentssubsequent to their stretching are: evaporative, such as Dry Ice pelletsmade from carbon dioxide, which may or may not have fibrous materialsincorporated within them for adherence to a filament-forming plastic;plastic solids, such as polyvinyl alcohol pellets, which may be washedfrom the fabric by a water solvent; frangible solids, such as starch,

glucose, diatomaceous earth, which may be ren duced to powder by impactor explosion and the powder removed by an air blast or suction;polytetrafluoroethylene pellets, which become nonadherent on quenching;sodium alginate, and other natural or man-made fibres which can beremoved from a finished fabric by means of an alkali or other solventwash; air bubbles made from dioctyl sodium sulfosuccinate, glycerine andwater, which explode under reduced pressure after passing out of the gunand/or ejector barrel; or the bubbles may be incorporated in thefilaments in the usual manner and left therein in the manufacture oflife preservers, air cushions, etc.

All such solids may be used for pulling and attenuating fibre-formingplastics into stretchoriented filaments; all such solids may bepropelled from a rotor in a constant stream and for substantialdistances, as from five to twenty feet, under a fluid pressure from 25to 150 pounds per square inch, or by centrifugal action.

Certain pulling solids, such as vermiculite, perlite, etc., may containfree moisture and/or water of constitution and when subjected to heatand pressure and the latter suddenly released, will result in the freemoisture or water of constitution being transformed into steam, therebyexploding, expanding, or exfoliating the solids and disrupting thecontacting plastic into adherent filaments. Other solids, which may ormay not contain free moisture and water of constitution, may be mixed,coated, or impregnated with: elastic fluids, such as steam; liquidfluids, such as water; or solids, such as carbon. These fluids andsolids, after being subjected to pressure, thermal or chemical treatmentto produce pressure, and the pressure suddenly released, will result inthe sudden expansicn or explosion of an elastic fluid, therebydisrupting the solids which they contact, impregnate, or with which theyare mixed. The filaments can then be stretch-oriented by the pullingforce of the exploded particles conveyed by their explosion gases orother conveying fluids; or the filaments may be stretch oriented by thepropulsion of the solids before explosion takes place, and theexploding, expanding, or exfoliating of the solids utilized as a meansof separating the solids from the filaments.

The fibre-forming materials and pulling solids may be conveyed onadiacent primary and secondary rotors, respectively, and the solidsbrought into adhesive contact by the converging arcuate paths of therotor peripheries. The said materials can then be positively drawn intofilaments by the diverging arcuate paths of the peripheries.

and the filaments subjected to a second and third stretching by thepropulsion of the solids from the secondary rotor during and subsequent,respectively, to the adherence of the filaments to the primary rotor.The setting of the filaments may be accomplished during the stretchingperiods, or after deposition, and as a result of cooling or quenchingfor a fibre-forming, heat reactive plastic, evaporation of solvent for afibre-- forming plastic in solution, or simply by stretching as in thecase of certain cellulosic derivatives.

The fibre-forming plastic may be charged onto the periphery of a primaryrotor in discrete portions uniformly spaced to contact discrete pullingsolids similarly spaced on, or uniformly distributed over, a' secondaryrotor; the plastic may be charged onto the periphery of a primary rotoras a film coating to contact discrete solids uniformly spaced on, ordistributed over, a secondary rotor; the use of pulling solids may beavoided altogether by the film coating, or uniformly spaced portions ofplastic, on the primary rotor contacting uniformly spaced points on thesecondary rotor and the stretch-orientation of the filamentsaccomplished by means of movement between the diverging paths of theperipheries of the two rotors; or the functions of the two rotors may becombined in one rotor by depositing the fibre-forming plastic andpulling solids in succession, one above the other.

To obtain and maintain adhesion between a heat reactive plastic andpulling solids until the filaments have reached their maximum stretch,the plastic may be heated to an adhesive condition prior or subsequentto deposition on a primary rotor; the solids may be heated sufficientlyprior or subsequent to deposition on a secondary rotor to cause theplastic to acquire fibre-forrm ing fluidity and become adhesive oncontact; or the plastic may be deposited in contact with the solids onone rotor and acquire fibre-forming fluidity prior or subsequent to thesaid contact.

The treating fluids for maintaining the filaments in, or returning thefilaments to, an adhesive condition for bonding purposes may be:

elastic oxidizing fluids, such as heated air, saturated steam, etc.;non-oxidizing elastic fluids, such as superheated steam, nitrogen, CO2gases, etc.; solvents, such as phenol and formic acid for polymericamide filaments, acetone for filaments spun from vinyl chloride-acetatecopolymers, etc.; non-solvent adhesives, such as starch, shellac,casein, latex, wax, acrylate resins, etc. Quenching or other settingfluids for the filaments may be: steam, water, oil, etc. for polymericamides; steam, heated air, etc. for removing an acetone solvent from acelluloseacetate solution; or the setting may be accomplished simply bymechanical stretching, as in the case of the filaments spun fromcellulose materials by orbweaver spiders. All such fluids for adhesion,quenching, sett ng, or other treating purposes, may be brought intocontact with the filaments and pulling solids during their con veyanceand deposition by the introduction of the former into, or their use as,the conveying and depositing fluids; or the deposited filaments andpulling solids may be subjected to such treating fluids by the usualspraying, dipping, or roller coating methods.

The invention is exemplified in the following descriptions, andpreferred arrangements are illustrated by way of examples in theaccompanying drawings, in which:

Fig. l is a vertical section of a gun and deposition drum for the makingof filaments and fabrics.

Fig. 2 is a fragmentary vertical section on an enlarged scale of theupper rotor shown in Fig. 1.

Fig. 3 is a-vertical section of a modified form of the gun shown in Fig.1.

Fig. 4 is a plan view of a fragmentary portion of the fabric produced bythe spinning gun and deposition drum shown in Fig. 1.

Fig. 5 is a plan View of a fragmentary portion of a modified fabricproduced bythe spinning gun and deposition drum shown in Fig. 1.

Fig. 6 is a plan view of a fragmentary portion of the fabric produced bythe spinning gunshown in Fig. 3 and deposition drum shown in Fig. 1.

Fig. 7 is a plan view of a fragmentary portion of a modified fabricproduced by the spinning gun shown in Fig. 3 and the deposition drumshown in Fig. 1.

Fig. 8 is a vertical section of a rotating valve for the end of the gunor ejector barrel.

Fig. 9 is a vertical section of a one-rotor spinning gun.

Fig. 10 is a fragmentary vertical section on an enlarged scale of therotor shown in Fig. 9.

Referring to the drawings more specifically by reference characters:

In Fig. 1, pulling pellets 2 in the hopper 3 are charged with the aid ofa feeding rotor 4 into the pockets or reservoirs 5 of the cylindricalliner s; and the latter encloses and turns with a top rotor l, equippedwith pockets 8 and radial passages 8, the pockets inthe liner andpockets in the rotor being connected by passages It as shown moreclearly in Fig. 2. In similar manher, the plastic pellets H in thehopper i2 are charged with the aid of a feeding rotor [3 into thepockets i l of the cylindrical liner I5; and the latter encloses andturns with a lower rotor it equipped with pockets l1 and radial passages18, the pockets in the liner and pockets in the rotor being connected bypassages l9. The liners for the two rotors, the two rotors, and theirrespective pockets are identical and all are enclosed by a casing 28.The upper rotor turns about a stationary cylindrical wall 2| which isequipped with axial upper and lower chambers 22 and 23, respectively,having connections 24 and 25, respectively, and ports 26 and 21, respectively. The lower rotor turns about a stationary cylindrical wall 28which is equipped with an axial chamber as having a connection 39 and aport 3!. A fluid treating nozzle 32 is inserted in the rotor casing.

Attached to the rotor casing is the breech of the gun barrel 33 enclosedwithin. a jacket 33a through which may flow a heating fluid, such asdiphenyl oxide, from inlet 3% to outlet 33c; and surrounding the outerend of the barrel is an ejector 34 having an inlet 35 and an outlet Asource of power, positioned externally of the rotor casing but notshown, is used to drive the upper and lower rotors in synchronizedrelation.

A depositing apparatus consisting of a foraminous drum 3'3 rotates aboutand in close contact with the stationary arms 33 of the cylindrical axis39, and the latter encloses: the chambers as, M, and 32, having ports43, 44, and 35, respectively, and connections 46, 47, and 48,respectively, to sources of suction; and a pressure chamber is having aport 56, and a connection 51 to a source of fluid pressure. Acompression belt 52 travels over adjustable compres- 'sion rolls 53 and5d, guiding rolls 55 and 5B, and under tension roll 51. Casing 58, seals59, and

suction compression rolls 6!! and 6!, enclose discrete fibers or othersolids as deposited from a blower upon an adjacent portion of the drum;and the solids are bonded during rotation of the drum by filaments fromthe spinning gun to form a fabric t2. A'fabric 63 is fed from the roll64 and deposited upon and bonded to fabric 62 as the.latter-is-fedbetween the compresison belt and drum. Housingfii enclosesa treating fluid suppliedby a nozzle 65, the fluid passing through thebelt, laminated fabrics, and foraminous wall. Pulling pellets madenon-adherent by quenching fluids will, upon impact with the drum, dropinto the trough Bi and be carried away by the conveyor B8. Theforaminous drum is driven from a source of power not shown and conveysthe laminated fabrics and belt, which conveyance maybeaided by adifferential pressure created by the treating fluid passing through thefabrics; or one of the rolls may be driven from a source of power notshown and the belt used to rotate the drum.

In Fig. 3, the upper rotor consists of a foraminous drum 69 whichrotates about the stationary arms '78, H, 72 and 13, the drum and armsthereby forming: a neutral chamber it having no connections; suctionchambers l5 and Hi, the former having a connection H to a source ofsuction, and'thetwo being connected by opening 58 in the arm H; havingan opening 86 and a blowing chamber 19 to a source of fluid pressure.The drum is supplied with a coating of fibres 8i furnished from thecarding and combing rolls 32 by an endless belt 83 which passes over aconveying roll 86. The lower rotor 85 is equipped on its peripheralsurface with small pockets or reservoirs 86 for the plastic fed thereinduring rotation of a screw Ell, which operates within the heated housing88; and the rotor turns about a fixed cylindrical axis 853 enclosing aheating chamber a!) supplied from a source of heat through an inletconnection 95. The gun barrel and ejector are the same as in Fig. 1except that no heating chamber is provided for the breech of the gunbarrel and a seal 92 makes connection between the upper portion of thegun barrelaand the top rotor. A doctor blade 93 is used to clip thefilaments from the lower rotor.

Fig. 4 shows a fragmentary portion of a fabric of tensioned filaments sproduced by the apparatusshown in Fig. 1, when the drum is rotatingsufiiciently rapidly, or the relative movement between the gun anddepositing surface is sufficiently great to maintain, or increase, thetension of the filaments as deposited on the drum in an intersectingcondition.

Fig. 5 shows a fabricof promiscuously intersecting filaments 95 producedby the same apparatus when the drum is not rotating sufficientlyrapidly, to maintain the tension of the filaments.

Fig. 6 shows the same fabric of tensioned filaments shown in Fig. 4 whenshort, discrete fibres 96 are used to pull the filaments, as in Fig. 3,and the fibres are bonded by the filaments.

Fig. '7 shows a fabric in Fig. 5 are used to bond Fig. 6.

Fig. 8 shows a valve suitable for connection to the end of the ejectorshown in Figs. 1 and 3. It consists of a spur gear 8?, keyed to the plug98, the former being used to rotate the latter in a casing 953 insynchronized relation with the rotors of the guns shown in Figs. 1 and3.

Figs. 9 and 10 show a one-rotor arrangement which the filaments of thepulling fibres of from into the breech of the gun barrel.

in which the rotor, liner, and axial cylinder are the same as those usedfor the pulling pellets in Fig. 1, except that a vertical division plateis required to separate the two chambers 22 and 23. An extrusion screwin close contact with the liner 6, as in Fig. 3, is utilized to chargethe upper portion of the pellet filled pockets with a fibre-formingplastic 100. Both pellet and plastic feeding devices are connected tothe housing I01, which encloses the rotor and is also attached to thegun barrel, 102, in which the fila ments, I03, are produced.

Example I In the manufacture of laminated layers of crepe wadding forpackaging purposes, polytetrafiuoroethylene propulsion pellets ofapproximately .06 inch in diameter are introduced into the hopper 3 ofFig. l at room temperature and fed into uniformly spaced pockets of theforaminous liner 6 of an upper rotor of about 12 inches in diameterwhile the latter is travelling at a peripheral speed of about 100 feetper min ute. The pellets are held in position under a differentialpressure produced by a vacuum of about 10 inches, the air passing fromthe liner pockets through passages iii of .04 inch in diameter, pockets8, radial passages 9, port 2'5, into chamber 23, and through the outlet25. Simultaneously, polyamide pellets of approximately the same diameteras the propulsion pellets and having a molecular weight of 20,000, arefed in similar manner from the hopper 12 into similarly spaced pocketsof the liner of a lower rotor of the same diameter and rotating at thesame peripheral speed as the top rotor. These pellets are brought tofibre-forming fluidity by contact with superheated steam of 320 F.temperature entering through connection and passing through the axialchamber 29, port 3|, radial passages I8, pockets ll, passages 19, andinto the pellet pockets M, those radial passages being cut off from thesteam pressure that would permit expulsion of the pellets from theirpockets.

After contact between the pulling pellets and the fibre-forming pellets,the latter adhere to the former as the peripheries of their respectiverotors pass through diverging arcuate paths, thereby causing eachfibre-forming pellet and that portion of the latter that adheres to apulling pellet to neck down and produce a positively stretched filamentbetween the corresponding pellet pockets in each rotor. As each radialpassage in the upper rotor becomes coincident with the port 26 a blastof heated CO2 gas at a pressure of lbs. per sq. in. from chamber 22results in the pulling pellets in the liner pockets connected with thesaid port being blasted there- This superfiuid secondary stretching ofthe filaments between their reservoirs and their respective pullingpellets exhausts the reservoirs of their spinning material.

To aid in the secondary stretching, the pulling pellets pass out of thegun barrel and into an injector barrel where the filaments are subjectedto a blast of cool air at 50 F. and velocity of 20,000 it. per min. toquench them. However, the

temperature of the quenching fluid may be anything below the softeningpoint of the filaments, such as 212 F. for saturated steam, roomtemperature for air, etc. The quenching of the filaments will result intheir being cold-drawn, and the polytetrafluoroethylene pellets becomingnon- 8 adherent on impact with the drum and dropping into the trough 61.

The filaments may also be subjected to a third stretching by thepropulsion of the pulling pellets after the former have been separatedfrom their rotor by exhaustion of the fibre-forming reservoirs, shearingof the filaments, or other means. If the second stretching operationresults in cold-drawing of the filaments, the third pulling operationwill result in an additional cold-drawing; if the secondary stretchingdoes not result in cold-drawing, the third stretching operation may ormay not result in cold-drawing, depending upon such factors as thetemperature and velocity of the ejector fluids, length of the gun andejector barrels, etc.

The third stretching of the filaments may even constitute a positivepull as when the filaments are deposited in an adhesive condition, orare held by suction on the depositing drum or other surface beforeseverance of the filaments from their rotor. In any event, the movementof the depositing surface, or relative movement between the gun anddepositing surface, should be sufliciently rapid to cause the filamentsto be deposited in a tensioned condition and in substantially straightlines between their bonding points, as indicated by the filaments 94 inFig. 4. For instance, if the filaments are travelling at the rate of2,500 ft. per min. at the time they are deposited, the peripheral speedof the depositing drum, or the relative speed between the movingfilaments and their depositing surface should be greater than 2,500 ft.per min; if the movement or the drum, or the said relative movement, isnot greater than the travelling speed of the filaments, the latter willbe deposited in a promiscuously intersecting condition, as indicated bythe filaments 95 in Fig. 5.

Flock, cellulose fibres or other solids from a disintegrating apparatus,such as that described in my U. S. Patents Nos. 2,152,901; 2,218,338;and 2,336,?45, are deposited upon that portion of the ioraminous drum Blrotating within the orbit of the casing 00, the conveying fiuid, such asair from a blower, passing through the drum, port 43, and outlet 00. Asthe drum rotates in the direction indicated by the arrow, the filamentsand other solids from a spinning gun are deposited upon the first webconveyed by that portion of the drum moving between the compressionrolls 0i and 53, the conveying fiuid passing through the webs, drum,port 40, and outlet M.

As the drum continues to rotate, a web crepe wadding ts from roll 04 isdeposited upon and bonded to the webs of intersecting filaments anddiscrete fibres. Or bonding of the three webs may be accomplished bypassing the webs between the drum and a foraminous belt 52, where thefilaments in the webs are treated to an activating or other fluid, suchas steam, solvent, heated air, etc., issuing from the nozzle 65 andpassing through the belt, webs, port 25, and outlet 48, the bondingbeing aided by the pressure exerted by the rolls and belt. The continuedrotation of the drum conveys the webs beyond the suction area wheretheir removal may be easily accomplished as a result of setting of thefilaments, preliminary coating of the drum with flock, and/or air orsteam blast passing through the drum from port 50 of the pressure fluidchamber 49. The laminated fabric may then be treated by spraying orother method to a water repellent, fire retardant, wetting agent, or acoating to make it impervious.

Obviously, the depositing of the three webs and the compression of anyone or all of them may take place in any desired order: A web of crepewadding may be deposited before the bonding filaments and both befollowed by a second web of crepe wedding; or a great many webs of crepewadding may be deposited and between each a web of bonding filaments toform a laminated structure of many layers such as would be required forinsulation or packaging purposes. In like manner, can bonding filaments,with or without layers of crepe wadding, be spun completely aroundarticles to be enclosed by the rapid rotation of the latter, or by arapid relative movement between the depositing fabrics and the articleto be enclosed.

Example II In the manufacture of enclosures for beef carcasses, sanitarynapkins, etc., cellulose or other discrete fibres 8! are parallelized,rolled, and thinned out by the conventional carding, combing and drawingequipment 82, and deposited as a web on the surface of a foraminousrotor 69, a indicated in Fig. 3; or the discrete fibres may be depositedon the rotor by a method similar to that just described for thedepositing drum. In any event, the discrete fibres are held on thatsection of the periphery of the rotor between arms 10 and 72 by suctionfrom outlet 71. A polyamide plastic is deposited in fibre-formingfluidity at a temperature of about 400 F. by extrusion screw 87 in thepockets or reservoirs of the lower rotor 85, both rotors being about 24inches in diameter and travelling at about the same peripheral speed asin Example I. The fibres and discrete and uniformly spaced portions offibreforming material contact one another and the latter is attenuatedinto filaments, as described in Example I.

As the periphery of the upper rotor reaches the position between arms 72and 13, the discrete fibres are subjected to a blast of elastic fluid,such as air, at room temperature and pressure of 50 pounds per squareinch from the inlet 80. This may be slightly in advance of exhaustion ofthe plastic pockets, or the shearing of the filaments bypolytetrafluoroethylene coated knife 93 from the plastic pockets on thelower rotor, which the filaments connect to the discrete fibres on theportion of the upper rotor about to be subjected to the blast of elasticfluid.

The other operations for stretching and depositing the filaments are thesame as described in Example I, except that the discrete pulling bresare deposited in a promiscuously intersecting condition and bonded bystretch-oriented filaments. If the movement of the depositing surface,or relative movement of gun and depositing surface, is sufficientlyrapid, the filaments will be deposited in a tensioned condition, asindicated by the filaments 94 in Fig. 6; if the said movement is notsufiiciently rapid both will be deposited in a promiscuouslyintersecting condition, as indicated by the filaments 95 and fibres 96in Fig. 7.

Meat, vegetables, fruit, etc. may be packaged thus in non-wovenenclosures of intersecting filaments spun about the foodstuff, theinterstices of the intersecting filaments then sealed by a spray, brush,or dip coating of gelatin, wax, or other suitable material; andsimultaneously with the sealing all air-pockets may be removed from thepackage by the cold-drawing of the filaments under a diiferential airpressure by means of a ,gun or ejector barrel to maintain connection toa vacuum pump. The foodstuff may be packaged while fresh and unfrozen,or it may be packaged subsequent to freezing; or the freezing may beaccomplished simultaneously with or subsequent to the packaging. Astrong, flexible, moisture-vapor-proof, and air-tight package can bespun about a beef carcass, and in close adherence to all sides of thecarcass, at the time and place required, which will effectively preventloss of moisture,-freezer burn, disoolorization and impairment of bloom.In similar manner, can enclosures be built about other kinds ofarticles, such as potted plants, which which require neither freezingnor exhaustion of air for their preservation. And when additionalsafeguards are required to avoid breakage or injury, the article may befirst enwrapped with crepe wadding or other soft resilient fibrousmaterial and then backed by a non-woven fabric of great strength, suchas that described above.

Example III In the manufacture of a flexible, fireproof in,- sulatingfabric, pellets or other discrete solids, containing free moisture orwater of constitution, such as vermiculite minerals, are substituted forthe polytetrafiuoroethylene pellets of Example I. The pulling pelletsare introduced into the pockets of the upper rotor in Fig. 1 andsubjected to saturated steam pressure of lbs. per sq. in. and atemperature of 350 F. from steam entering the inlet 25. The pullingsolids are propelled within the gun barrel by steam at lbs. per sq. in.entering the pockets from inlet 24, a vertical division plate being usedto divide the two pressure chambers 22 and 23, as in Fig. 9. The lengthof the gun and/or ejector barrels may be regulated and muzzle areasrestricted so that explosion of the pulling solids cannot take placeuntil after emission of the solids from the barrel. Or a rotating valve,such as described in Fig. 8, may be attached to the muzzle of either thethe necessary pressure in either or both barrels before explosion takesplace. In such a case, the rotation of rotor and valve may besynchronized so that propulsion of the pellets will occur slightly inadvance of the opening of the valve. The exploding of the solids willseparate the latter from the filaments, and both may then be depositedto form a fabric in which the expanded or exploded solids are bonded bystretch-oriented, tensicned or non-tensioned, filaments, as described inthe above examples.

Obviously, vermiculite solids may be expanded in a prior operation, theexpanded or exploded solids distributed uniformly over the foraminousperiphery of the top rotor in Fig. 3 in a second operation, and thefilaments stretched and deposited, as already described, to form thesame kind of fabric.

Example IV In the manufacture of filter fabrics, frangible, diatomaceousearth, pulling pellets, loosely bonded by pressure and free moisture,and polyethylene fibre-forming pellets of 20,000 molecular weight aresubstituted for the pulling and spinning pellets, respectively, inExample I, and the former exploded as in Example III. The resulting dustwith filaments are deposited on the drum by the conveying fluid passingthrough the drum, and the dust is bonded by the filaments. In this case,the fibre-forming polymer may have an initial velocity of 200 ft. permin. for its primary stretching, and this may be speeded up to 2,000 ft.per min. during deposition by a blast of superheated steam at atemperature of 400 F. from the ejector, which temperature in the ejectorwill be sufficient to maintain the filaments in an adhesive condition ata much lower temperature during deposition. After the secondarystretching the plastic reservoirs are subjected to a blast of cool airat a temperature of 50 F. from nozzle 32 to render the residuenon-adherent to the pockets in a polytetrafiuoroethylene liner.

By using a pulling pellet rotor, as shown in Fig. 1, feeding thepolyethylene into plastic reservoirs, as shown in Fig. 3, and speedingup the rotors to give a peripheral speed of 10,000 ft. per min, it ispossible to throw the diatomaceous earth pellets out of their reservoirsby centrifugal action and thereby stretch the filaments without the aidof suction or pressure from the axial chambers of either rotor. Thecentrifugal action results in the pellets striking the sides of thebreech of the gun barrel and disintegrating into powder, and the latterwith the stretched filaments being conveyed by air entering the breech,where the seal 92 in Fig. 3 is omitted, induced by the fluid streampressure from the ejector. The air stream redirects the movement of thefilaments on disintegration of the pellets, and coating the breech ofthe gun barrel with polytetrafluoroethylene prevents sticking of thefilaments to the breech during the said redirection.

Example V In the spinning of protective fabrics over freshl'y seededground to prevent injury from frost, escape of moisture, baking of theearth, etc, a copolymer of vinyl chloride and vinyl acetate may bebrought to fibre-forming fluidity when used in the proportion of 13 percent vinyl chloride, 2 per cent vinyl acetate and 85 per cent acetone.The solution is charged into the reservoirs of a primary rotor by meansof an extrusion screw, as in Fig. 3, to contact fertilizer pullingpellets fed into the pockets of a secondary rotor, as in Fig. 1, bothtravelling at a peripheral speed of 100 ft. per min. The pellets arepropelled by an air blast from inlet 24 and both filaments and pelletsare conveyed in an air stream through two ejectors, the first as alreadydescribed, and the second positioned on the barrel of the first. Thefirst ejector is used to coat the filaments with aluminum powder whilethe filaments are still in an adhesive condition, and the second coatsthe aluminum covered filaments with an animal glue so that the filamentsadhere to one another as deposited over the ground. Weatheringconditions will disintegrate the fertilizer pellets almost immediatelyand ultimately cause the disintegration of the fabric when the need forsuch a protective covering is past.

In this example, the acetone is dissipated in the air and cannot berecovered. It is therefore usually advisable to use a suitablefibre-forming plastic that can be brought to a fibre-forming fluidity byheat, stretched into filaments, and the latter bonded to one another,all without the use of a solvent.

Example VI In the spinning of certain fabrics for clothing, insulatingpurposes, etc, cellulose acetate may be extruded at a temperature of 400F. as a film coating over a primary rotor to contact uniforznly spacedpoints or areas on, or the spaces between the pockets of, a secondaryrotor. After primary stretching, the filaments are clipped at either endby doctor blades or the sharp edges of the breech of the gun barrel; andsubsequently to their severance, they are conveyed through an ejector inan adhesive condition and coated by aluminum powder. The aluminumcovered filaments are then deposited on the drum and held in position bysuction until bonded together by adhesive tape or a fabric from roll 64;or they may be bonded into an integral fabric by an adhesive spray fromnozzle 66, or an adhesive roller coating from the belt 52. Or thefilaments without an aluminum coating may be deposited on the drum in anadhesive condition and bonded to aluminum foil from roll 64 as both arefed between the compression rolls and drum.

Obviously, a film coating on a primary rotor may contact eitheruniformly spaced, or uniformly distributed, pulling solids on asecondary rotor, and subsequent operations accomplished as alreadydescribed. However, in the latter case, the spacing of the filamentswill not be uniform. Or a suitable plastic may be charged into thepockets of a primary rotor in fibre-forming fluidity, or in solid form,and brought by heat to fibre-forming fluidity, and contacted withuniformly spaced points on a secondary rotor and attenuated intofilaments without the aid of pulling solids, as described into the aboveexample.

Example VII In the manufacture of abrasive sheets for sanding belts,safety walks, etc, corundum pellets are used for stretching vinylidenechloride filaments and both are used under substantially the sameconditions as those described in Example I, except that the corundumpellets are incorporated in the fabrics as a plurality of layers arebuilt upon an endless carrier. Or the abrasive pellets may be preheated,or heated in hopper 3 to a suitable temperature, to contact unheatedplastic pellets at a temperature of 400 F., and the stretching anddeposition on the drum accomplished, as already described. The abrasivesolids after being bonded by stretch-oriented filaments can then receivea paper or cloth backing from roll 64.

Example VIII In the spinning of fabrics for various purposes, a singlerotor may be substituted for the two rotors in Example I, and moltenpolyamide fibreforming polymer deposited by an extrusion screw as a filmcoating I00 over the polytetrafiuoroethylene pellets and pockets, asshown in Figures 9 and 10. The film coating may not completely cover thepockets but it will restrict the size of the opening through which thepellet will be propelled, and the propulsion of a pellet will result inthe plastic at the sides of the pocket being drawn into two or morefilaments. Obviously, the shape of the pocket may be made to regulatethe number and shape of filaments produced.

It is also evident that: smaller fibre-forming solid pellets may be fedinto a pocket above and at the side of a larger pulling pellet and theformer brought to a fibre-forming fluidity by steam at a suitabletemperature from connections 24 and 25, as already described; afibreforming pellet or pellets may be fed into a pocket and held thereby suction or by bringing the pellet or pellets to an adh sive fluidityby a suitable heated fiuid from connection 25, and the pulling pelletdeposited in the pocket above and in contact with the fibre-formingpellet or pel-' lets; or a fibre-forming film coating and uniformlydistributed pulling solids may be deposited on the rotor in superposedrelation, and the propulsion and stretching operations accomplished asalready described.

.While specific sizes, velocities, temperatures, etc., have been givenin the examples cited, it is obvious that they may vary within widelimits. For instance, the molecular weight of the fibreforming plasticsmay vary between 10,000 and 50,000; the sizes of the rotors may be 6 in.dia. for laboratory work, or they may be 6 ft. for plant scaleproduction; the peripheral speed of the rotors may be 1 ft. per min., orit may be 10,000 ft. per min.; the weight of the pulling pellets may begrain, troy weight, for perlite pellets used in insulation fabrics or 3grains, troy weight, for polytetrafiuoroethylene pellets required in themanufacture of packaging materials; the fibreforming fluiditytemperature of the plastic may be 500 F. for a polymeric amide oratmospheric temperature for a vinylchloride resin; the velocity of thepropulsion fluid may be anything that will propel the pulling pellet, orit may be 50,000 ft. per min. for an inert nitrogen gas required forstretching a polyamide filament; and these values may vary much morethan indicated by the above figures.

. It will be obvious from the foregoing descriptions that stretching ofthe filaments may be accomplished by a great variety of methods: apositive stretching between the rotors; a superfluid stretching betweenfiuid-conveyed pellets and the pockets for the fibre-forming plastic inone of the rotors; a super-fluid stretching by propulsion of the pelletspulling trailing filaments; a positive pull between a depositing surfaceand the said pockets of one of the rotors; and propulsion by centrifugalaction may be substituted for the stretching by other means.

It will also be evident that cold-drawing of the filaments may beaccomplished in any one or all of the said stretching operations byvarying the conditions of the treating fiuids indicated; and if thefilaments are deposited in a set condition, they must be made adhesiveduring or prior to deposition or else be held in position by suctionwithin a depositing drum, or vacuum produced within the article beingpackaged or otherwise enclosed, until activated or made adhesive, as.already described.

It will be understood throughout the specification and appended claimsthat: a tensioned filament is a filament that is held taut between twopoints; an integral fabric of tensioned filaments is a fabric in whicheach filament is held taut between the points of intersection at thetime of bonding; and superfiuid pulling or stretching force means aforce in excess of that which can be produced by a fiuid stream alone.

I claim as my invention: 1

1. In a method for attenuating fibre-forming material into filaments bypropulsion of discrete solids adherent therewith, the steps comprising:depositing the said solids upon a retaining wall; moving the said wallthrough an endless circuit to bring the said solids into adheringcontact with the said material; and propelling the said solids with aportion of the said adherent material from the said wall during the saidmovement to attenuate the said material into a continuous succession ofdiscontinuous filaments of substantial length and strength,

2. In the method of claim 1, the said steps in which the said propulsionforce is exerted against all 14 the said solids in a directiontransverse to the movement of the said wall.

3. In the method of claim 1, the said steps in which the said propulsionforce is a fluid stream. 4. In the method of claim 1, the said steps inwhich the said propulsion force is an elastic fluid.

.5. In the method of claim 1, the said steps in which the saidpropulsion is by force of centrifugal action.

6. In the method of claim 1, the said steps in which the said propulsionforce is a quenching fiuid to set and cold-draw the said filaments.

7. In the method of claim 1, the said steps in which the said filamentsare set and attenuated to the initial point of their elasticity duringthe said propulsion of the solids.

8. In the method of claim 1, the said steps in which the said contact ismade with finely divided portions of the said material.

9. In the method of claim 1, the said steps in which the said wall isforaminous, and the said propulsion is exerted by passage of a fluidstream through the said wall.

10. In the method of claim 1, the said steps in which the said wall isforaminous, and the said solids are maintained in position on the saidwall by suction exerted within the wall, and are propelled from the wallby fiuid pressure passing through the wall.

11. In the method of claim 1, the said steps in which the said materialis organic and the said solids are inorganic.

12. In the method of claim 1, the said steps in which the said materialand said solids are deposited on the said wall in superposed relation.

13. In the method of claim 1, the said steps in which the said filamentsare produced attached to the said solids, and including the additionalstep of separating the said solids from the said filaments.

14. In the method of claim 1, the said steps in which the said movementis a continuous rotation of the said wall during which the saidoperations are constantly repeated to produce filaments of from 5 to 20feet in length.

15. In the method of claim 1, the said steps in which successiveportions of the said material contact successive portions of the saidsolids, and the said solids are propelled at comparatively great speedby a succession of impulses to produce a constant flow of filaments.

16. The method of producing discontinuous filancients of substantiallength and strength from a fibre-forming material comprising: depositingthe said material upon a primary wall; depositing discrete solids upon asecondary wall; moving the said walls through endless circuits thatconverge and diverge whereby the said material and said solids arebrought into adhering contact during the converging movement and thesaid material is attenuated into discontinuous filaments during thediverging movement; and propelling the said solids from the saidsecondary wall during the said diverging movement, by force of a fluidstream to increase the attenuation of the said filaments.

17. The method of claim 16 in which the said material is deposited infinely divided portions.

18. The method of claim 16 in which the said solids are deposited inuniformly spaced portions.

19. The method of claim 16 in which the said material is deposited infinely divided portions, and the said solids are deposited in spacedrelation to register with the said portions, during the said movementsof the walls.

20. The method of claim 16 in which the said attenuation of the saidmaterial into filaments is accomplished at comparatively slow speed, andthe said increase in attenuation of the filaments is accomplished atcomparatively great speed.

21. The method of claim 16- in which the said solids are separated fromthe said filaments by disintegration of the solids.

22. The method of claim 16 in which the said solids are separated fromthe said filaments by explosion of the solids after the said increase inattenuation of the filaments.

23. The method of claim 16 in which the said solids are separated fromthe said filaments, after deposition of the filaments, by passing asolvent for the solids through the deposited filaments.

24. The method of claim 16 including the steps comprising: severing thesaid filaments from the said primary wall; and propelling the saidsolids after the said severance to give additional stretch to the saidfilaments.

25. The method of claim 16 in which the said material is deposited indiscrete solid portions, and the said solid portions reduced tofibre-form ing fluidity by heat during the said movement of the primarywall.

26. The method of claim 16 in which the said material is deposited indiscrete solid fusible portions, the said portions reduced by heat tofibreforming fluidity during the said movement of the primary wall, andthe said fiuid portions while still unset and nonelastic attenuated intofilaments.

27. The method of claim 16 in which the said material acquiresfibre-forming fluidity at temperatures between atmospheric and 500 F.,and the said solids remain noniusible at the said temperatures, duringthe said movements of the walls.

28. The method of making a nonwoven fabric comprising the method ofclaim 16 for producing filaments which are attached in predeterminedrelation to the said solids, and including the step of depositing thesaid filaments and said solids in the said predetermined relation toform a web.

29. The method of claim 28, including the steps of passing a wash fluidthrough the said web to remove the said solids, and bonding the saidfilaments to one another.

30. The method of claim 28, including the step of bonding the saidsolids by the said filaments.

31. The method of claim 30 in which the said bonding is accomplished bydepositing the said laments in an adhesive condition.

32. In an apparatus for producing fibres, the combination of: primaryand secondary rotors having peripheral walls that converge and divergewith each other in their movements through endless circuits; means forsupplying a fibre-forming material to at least one of the said walls,the walls being so constructed and arranged that they are adherentlyconnected by the material during their said converging movement, and thematerial is attenuated into fibres during their said diverging movement;and means for discon-' meeting the ends of the said fibres from one ofthe said walls and increasing the stretch of the fibres before theirseverance from the other of the said walls.

33. In an apparatus for producing fibres, the combination of: primaryand secondary rotors whose peripheral surfaces converge and diverge witheach other during their rotative movements; a primary feeding means forsupplying fibreforming material to the said peripheral surface of theprimary rotor; a secondary feeding means for suppiying discrete solidsto the said peripheral surface of the secondary rotor, the said rotorsbeing so constructed and arranged that the said solids and the saidmaterial are adhesively contacted during the said converging movement,and the said material is attenuated into discontinuous fibres ofcomparatively short length during the said diverging movement; and meansfor supplying a propulsion fluid to blast the said solids from thesecondary rotor during the said rotative movements whereby the saiddiscontinuous fibres oi comparatively short length are removed fromconnection with the secondary rotor and stretched into discontinuousfibres of substantial length by pull of the solids conveyed by the saidpropulsion fiuid.

3 In an apparatus for producing nonwoven fabrics, the said combinationof claim 33 in which the said fibres of substantial length are attachedin predetermined relation to the said solids, and including: aforaminous retaining structure adapted to move through an endless path;means Within the said structure for drawing the said propulsion fiuidtherethrough to deposit the said solids and fibres thereupon during acontinuous movement of the structure through the said path; and meansfor bonding the said deposited fibres and solids in the saidpredetermined rela tion into an integral fabric.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 692,631 Cooley Feb. 4, 1902 1,137,814 Von Pazsiczky May 4,1915 2,159,945 Slayter Mar. 21, 1939 2,156,455 Kleineet al. May 2, 19392,181,043 Boeddinghaus Nov. 21, 1939 2,278,895 Rugeley et al. Apr. '1,1942 2,326,174 Rutishauser Aug. 10, 1943 2,357,392 Francis Sept. 5, 19442,369,506 Weibel Feb. 13, 1945 2,37%,549 Hall Apr. 24, 1945 2,385,358Hanson Sept. 25, 1945 2,411,660 Manning Nov. 26, 1946 2,437,264 ManningMar. 9, 1948 2,509,735 Horsak May 30, 1950 2,522,526 Manning Sept. 19,1950 OTHER REFERENCES Gersch, pp. 152 to 158 and 189 of April 1947 issueof Natural History.

1. IN A METHOD FOR ATTENUATING FIBRE-FORMING MATERIAL INTO FILAMENTS BYPROPULSION OF DISCRETE SOLIDS ADHERENT THEREWITH, THE STEPS COMPRISING:DEPOSITING THE SAID SOLIDS UPON A RETAINING WALL; MOVING THE SAID WALLTHROUGH AN ENDLESS CIRCUIT TO BRING THE SAID SOLIDS INTO ADHERINGCONTACT WITH THE SAID MATERIAL; AND PROPELLING THE SAID SOLIDS WITH APORTION OF THE SAID ADHERENT MATERIAL FROM THE SAID WALL DURING THE SAIDMOVEMENT TO ATTENUATE THE SAID MATERIAL INTO A CONTINUOUS SUCCESSION OFDISCONTINUOUS FILAMENTS OF SUBSTANTIAL LENGTH AND STRENGTH.